[The effect of substitution of soybean meal 44% in the diet of SilverMontazah chickens and hens by algae meal (40.59%) at levels of 0%, 25%50% and 75%.The obtained results are summarized as follows:Live body weight:-There was an increase in live body weight (10.2-18.8%), (7.2-20.5%) and(5.9-28.5%) at 25% algae meal level than other treatments.-The highest body weight was at 25% algae meal level.-The worst body weight was at 75% algae meal level.Body weight gain:-Itwas noted that the best weight gain was in level 25% algae meal, aswell as in 50% algae meal at week 4 till 20 weeks of age, while atlevel 75% the lower in body weight gain was detected.Growth rate:-There was an increase in growth rate at level 25% algae meal at weeks 2till 6 weeks of age than other treatments (T1, T3, andT4).-Increasing algae meal increased growth rate at weeks 7-20 weeks.-Increasing algae meal decreased growth rate at weeks (0-4,5-8,9-12 and 0-12)-75% algae meal was the worst in the growth rate.Feed consumption:-Increasing the level of algae meal decreased feed consumption -Birds fed 75% algae meal consumed less than other treatments.Feed conversion:- The best treatment in feed conversion was 25% algae meal level until 12 weeks of age.-On contrary 75% algae meal level was the best in feed conversion from 16-20 weeks of age.Sexual maturity: - The age of sexual maturity decreased with the increased level of algae meal up to 50%.- Birds need more time to arrive sexual maturity for T1 and T4 algae meal groups than T2 and T3.- Body weight increased as algae meal increased up to 50% then body weight decreased at 75% algae meal group.- Egg weight improved with increased the level of algae meal up to 50%.Mortality-Increasing the algae meal levels in the diet decreased percentage.Carcass:- There was increasing of heart, heart%, gizzard, spleen, spleen% andG.L.H at Level 25% algae meal.- The Liver and liver % was increased at level 50% algae meal.- The dress was increased in chicks fed diet control and 25% algae meal (74.11, 70.34), respectively.- Level 75% algae meal was the worst in all traits.Second experiment:Live body weight:-Increasing the levels of algae meal from 0% to 75% significantly (p<0.05) decreased average body weight.-Level at 25% algae meal was the best in body weight significantly(p<0.05).Feed consumption:-Diets have nearly the same calories 2718.51, 2731.77, 2778.9 and2792.69 respectively.- The feed consumed for the three treatments were equal in 22 until 30 weeks of age.-Daily feed intake decreased with increasing algae meal.Feed conversion:-Increasing the level of algae meal up to 50% improved significantly (p<0.05) feed conversion.- T2 and T 4 (25 and 75%) algae meal had the worst feed conversion.Egg number:-Eggproduction for 4 treatments through the 8 experimental 4-week periods.It has been observed that increasing algae meal level from control (TI)to 50% (T3) increased significantly average egg number.-T4 (750/0) decreased significantly (p<0.05) average egg production/ hen/ period

-Birds fed control diet reached its peak production at 34-weeks of age.-Level 50% algae meal reached its peak production at 30-weeks of age recording the highest level among other treatments.-Birds fed 75% algae meal was inferior in egg number throughout the experimental period.Egg weight:- Increasing the level of algae meal increased egg weight up to 50% algae meal then decreased at level 75%.-Level at 50% algae meal produced the high egg weight than other treatmentsEgg mass:-Level at 50% algae meal was the highest egg mass in all ages.- Egg mass of birds fed control diets increased than other treatments (25% and 75%) algae meal.-Level at 75% algae meal was the worst in egg mass.Egg quality:Egg weight -At level 25% algae meal was highest than other treatments fu eggweight-Eggweight at 30-34 weeks of ages increased significantly (p<0.05) whileat 38, 42 and 46 weeks of ages the increase was not significant.Shell weight%:-There was a significant difference of shell weight at ages 30,34,38,42 and 46 weeks of ages.-Shell weight percentage was the heaviest at level (0 and 500/0) of algae meal.-Level at 75% algae meal decreased shell weight percentage.Shell thickness:-No difference among shell thicknesses in all level at 30,34 weeks.-Ages at 38, 42 and 46 weeks of age were significantly (p<0.05) in shell thickness.-Shell thickness increased until level 50% of algae meal.Haugh units:-No significant differences among level 0%, 25%, 50% and 75% in all ages until 42 weeks of age.- There were a significant differences (p<0.05) among all levels of algae meal at week 46.Yolk color:-There were a significant differences (p<0.05) in yolk color in weeks30, 34, 42 and 46 except 38 weeks of ages no significant difference of_yolkcolor was observed.. Yolk color increased with increasing level of algae meal.- 75% algae meal level was the highest in yolk color.Shape index:-There were no significant differences in shape index at weeks 30, 38, 42, and 46 weeks of age.- There was a significant difference (p<0.05) in shape index at week 34.Yolk index:- There were no significant differences in yolk index at 30, 34, 36, 42 and 46 weeks of age.-At level 0% the highest in yolk index while, at level 25% algae meal the worst in yolk index.Fertility percent: -Level at 50% algae meal was the best in fertility percent than other treatments.-Level at 75% algae meal the worst in fertility percent.Hatchability percent: -It was noted that 50% algae meal increased hatchability (p<0.05) than other treatments (TI, T2 and T4).Mortality:-Mortality percent in all birds increased with increasing level of algae meal from 0% to 75% of Silver Montazah hens.Carcass traits:- The level of algae meal at 50% increased heart, liver, heart% and dress.-Level 25% of algae meal increased spleen, spleen% G.L.H, gizzard, gizzard% than other treatments.-Dressing percentage increased significantly at 25 % algae meal thanother treatments.-Level 75% algae meal (T4) was the worst in all traits.Blood samples:-Increasing the level of algae meal in the diet did not affect total protein, albumin, globulin, NG ratio and glucose.-Level at 75% algae meal decreased total lipids and cholesterol.Digestibility coefficients:-There were no significant differences (p<0.05) among treatments unless digestibility coefficients of dry matter.-Level 250/0 algae meal the highest of dry matter than other treatments.-Increasinglevel of algae meal to 50 or 75% decreased significantly (p<0.05)dry matter crude fiber, ether extract and nitrogen free extractdigestibilities.-Digestibility coefficient of crude protein improved as the level of algae meal increased until 50%.Physical and chemical analysis:- Increasing the level of algae meal increased WHC, TEND and color significantly (p<0.05).-Birds fed 25% algae meal had the highest pH than other treatments respectively.-Increasing the level of algae meal fed to different groups caused asignificantly increase (P<0.05) in the level of dry matter and crudeprotein but decreased in ash and ether extract.Economic efficiency:-The total feed consumption was decreased by increasing algae meal level in the diet.- The price/kg diet was decreased by increasing algae meal in the laYing diet.-Netrevenue was the highest in case of diets contained 50% algae meal(11.68 LE/hen), after which it decreased to reach (4.63 LE/hen in 25%and 7.37LE/hen for 75%) algae meal.